Articles
Atmospheric Science
January 2010 Vol.55 No.1: 77–83
doi: 10.1007/s11434-009-0584-6
SPECIAL TOPICS:
On linking climate to Chinese dynastic change: Spatial and
temporal variations of monsoonal rain
ZHANG DeEr1, LI Hong-Chun2,3*, KU Teh-Lung2,4 & LU LongHua5
1
National Climate Center, Beijing 100081, China;
Department of Earth Sciences & Research Center of Ocean Environment and Technology, Cheng-Kung University, Tainan 70101, Taiwan, China;
3
School of Geographical Sciences, Southwest University of China, Chongqing 400715, China;
4
Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089, USA;
5
Chinese Academy of Meteorological Sciences, Beijing 100081, China
2
Received June 22, 2009; accepted August 3, 2009; published online November 20, 2009
The causal correlation or linkage between the East Asian Monsoon (EAM) intensity and rise/fall of Chinese dynasties recently
proposed by high-resolution paleoclimate reconstructions is examined in detail. Aside from many exceptions to the correlation,
both instrumental and historical climate records show strong spatial variations of rainfall on annual-to-decadal scales over eastern
China. The relationship between rainfall and EAM intensity also exhibits regional disparity. These observations suggest: (1) Taking paleo-proxy records from a single locality in eastern China to imply changes in drought/wetness as to affect the cultural and
political history of China is fraught with uncertainty. (2) On annual-to-decadal scales, the thesis that δ18O in speleothems can
be used as a proxy for the EAM strength lacks empirical underpinnings.
east Asian monsoon, stalagmite δ18O record, rainfall records, Chinese dynasties changes, historic climates
Citation:
Zhang D E, Li H C, Ku T L, et al. On linking climate to Chinese dynastic change: Spatial and temporal variations of monsoonal rain. Chinese Sci Bull,
2010, 55: 77–83, doi: 10.1007/s11434-009-0584-6
East Asian Monsoon (EAM) plays an important role in affecting rainfall in China. There is a substantial body of published work on the influence of modern-day EAM upon
precipitation variations in this big, populous country of Asia.
Past variations of EAM have been studied through proxy
records archived in natural deposits such as loess sequences,
lake sediments and cave stalagmites. Reports on Holocene
and late Pleistocene stalagmite δ 18O proxy records [1–5]
with resolutions of 1–100 years have attributed the wet
conditions over eastern China to enhancement of East Asian
Summer Monsoon (EASM) caused by increased solar insolation and North Hemisphere temperature. One such record
from Wanxiang Cave in Wudu County, Gansu Province,
has been taken to suggest a causal correlation or linkage
between the EASM strength and the Chinese dynastic
change [5], a proposal made earlier in the study of Lake
Huguang Maar in Zhanjiang City, Guangdong Province [6].
The proposition has engendered interest as well as debate
[7,8]. These studies of high-resolution paleoclimate reconstruction, with interpretations on phenomena (e.g., EASM)
and events (e.g., culture/history) ranging from orbital to
sub-decadal scales, have raised the following issues: Does
the linkage exist? On annual-to-decadal resolutions, does
rainfall in eastern China show a direct correlation with
EASM strength, and how broad a region can a single
EASM-strength record represent the dry/wet condition of
eastern China?
*Corresponding author (email: [email protected], [email protected])
The Chinese dynastic turn of fortune may have spanned as
© Science China Press and Springer-Verlag Berlin Heidelberg 2009
1 Correlation between EASM strength deduced
from the WX42B δ18O record and Chinese dynastic change —a reappraisal
csb.scichina.com www.springerlink.com
78
ZHANG DeEr, et al. Chinese Sci Bull January (2010) Vol.55 No.1
short as several decades. Thus correlating proxy signals to
dynastic changes requires the capability of resolving the
proxy record to time intervals of 1–10 years. Encouragingly,
such a capability appears attainable [5,6], and it can be
gleaned from Figure 1. In this figure, Zhang et al. [5] use
δ 18O in stalagmite WX42B in Wanxiang Cave as proxy for
the EASM strength. They correlate three periods of dry
climate brought forth by weak EASM (heavy δ 18O, marked
by unnumbered yellow vertical bars) with the demise of the
Tang, Yuan, and Ming dynasties, and one period of strong
EASM (light δ 18O; unnumbered green bar) with the auspicious onset of the Northern Song Dynasty. The correlations
led to the suggestion that climate played a key role in affecting these dynastic changes. Left unsaid from the Figure
1 record, however, are additional four intervals of heavy
δ18O and three intervals of light δ 18O, during which social
conditions in China were exactly opposite to those implied
by the aforementioned correlations.
The four heavy δ 18O periods (green bars ①–④ in Figure 1): 1020–1070 A.D. (mid-Northern Song Dynasty),
1400–1435 A.D. (early Ming Dynasty), 1490–1540 A.D.
(mid-Ming Dynasty), and 1660–1700 A.D. (early Qing
Dynasty) were well-known times of stability, prosperity,
and cultural accomplishments. The mid-Northern Song
Dynasty included the reign of Song Ren Zong (1023–1063
A.D.), considered one of the golden periods in Chinese history [9]. As China’s “most durable dynasty” [10], the Ming
Dynasty in its early era saw Zheng He’s seven expeditions
to the South China Sea, the Indian Ocean, and beyond
(1405–1433 A.D.). These record-breaking seafaring adventures, as well as the great territorial annexation under the
reign of Emperor Kang Xi in the early Qing Dynasty, ex-
emplified China’s flourishing power[11]. So were the cultural and artistic attainments during the middle part of the
Northern Song and the Ming dynasties. On the other hand,
the three light δ18O intervals (yellow bars ⑤–⑦ in Figure
1) identified with strong monsoons were times of warfare,
social upheaval and population declines that doomed the
dynastic power base. These periods include the 6th century
(late South and North dynasties), the first part of 12th century (demise of the Northern Song Dynasty), and the late
19th-to-early 20th century of a weakened Qing Dynasty
coping impotently with foreign powers (e.g., 1858–1860
A.D. Treaties of Tientsin and Peking and the 1896–1900
A.D. Boxers’ Uprising) and ending with the 1911 A.D.
Revolution [9–11].
Also noteworthy in the Wanxiang Cave record is the
light δ 18O interval marked as NSSMP (Northern Song
Strong Monsoon Period, 960–1020 A.D.). Described as
“rapid increase in rice cultivation, dramatic increase in population, and the general stability at the beginning of the
Northern Song Dynasty” [5], NSSMP actually coincided in
large part with a period of relatively unstable social milieux.
War raged through the early period (960–997 A.D.) of the
Northern Song Dynasty, and the southward extension of the
kingdom did not come to a close until 980 A.D. [9,11,12]. During this period, the population increase was sluggish. In fact,
most of the Northern Song population increase occurred during 1000–1100 A.D. [12], a period when the δ 18O of
WX42B turned heavier rather than lighter (Figure 1).
In summary, periods of heavy and light δ 18O values in
the Wanxiang Cave record may relate to times of either
social stability or turmoil in Chinese history, defying meaningful correlations. As variations of δ 18O in stalagmites
Figure 1 Correlation between the EASM strength and Chinese dynastic fortune. Changes in the EASM strength are deduced from the δ18O record in stalagmite WX42B from Wanxiang Cave [5]. The average δ18O of –8.17‰ is indicated by the horizontal dashed line. Notations are the same as in Figure 1 of
[5], from which the present figure is modified. The four periods ①–④ of dynastic prosperity and the three periods ⑤–⑦ of dynastic decline shown here
contradict the δ18O-dynastic fortune correlations of [5].
ZHANG DeEr, et al. Chinese Sci Bull January (2010) vol.55 No.1
have been interpreted to reflect changes in the strength of
EASM [1–5], any causal relationships between EASM and
Chinese dynasty changes remain equivocal. This equivocalness also applies to the Lake Huguang Maar data [6].
Inferences derived from this lake sediment record for low
rainfall in China during the last 30 years of the Tang Dynasty [6] contradict the Chinese historical accounts [7,13].
The conclusions drawn from both the Zhanjiang and Wudu
records regarding monsoonal influences on dynastic
changes [5,6] are thus open to scrutiny as to their veracity.
2 Comparison of proxy-based records with Chinese historic documentations on climate
In order to validate the proxy-based paleoclimate records,
their crosschecking with historic accounts of past climate
change should be of great value. Chinese historical documentations are generally accurate in chronology and unambiguous in their description of dry/wet and warm/cold conditions[14–18]. Over much of Chinese history, the
79
region encompassing approximately 100°–125°E and
20°–40°N, termed hereafter the “whole eastern China”, has
remained the primary domain of economic, cultural, as well
as political activities. In considering climate as a vital factor
affecting these activities in China including dynastic change,
one should put this broad region into context unless cases to
the contrary are specifically documented. Under this geographic context, one notes from the historical recording [15]
shown in Figure 2 that a wet condition prevailed over the
whole eastern China during the late Tang Dynasty. This wet
condition is at odds with the proposed linkage [6] between
dry climate (indicated by the high Ti in Lake Huguang
Maar sediments) and the dynasty’s collapse.
Notable discrepancies between the records of Lake Huguang Maar and Wanxiang Cave (Figure 2) present somewhat a puzzle as both records reflect EAM strength variations[5,6]. While age uncertainties may play a part, the discrepancies raise the issue of whether regional rainfall also
plays a role; namely, whether the EASM intensity and regional rainfall bear a direct relationship. We shall address
this issue below.
Figure 2 Comparison of records based on proxy measurements and historical documentation. Data sources: Ti [6]; δ18O [5]; 1500-year dry-wet index series [16]; 500-year dry-wet index series [17, 18]. Thick red curves are 50-year running averages of the decadal data sets of thin red curves. Thick blue curves
are 10-year running averages of the annual data sets of thin blue curves. Agreement between the thin red curves and the thick blue curves reassures the data
quality. Note the disparities between the proxy and historical records for the three weak monsoon periods of late Tang Dynasty (LTWMP), late Yuan Dynasty (LYWMP) and late Ming Dynasty (LMWMP).
80
ZHANG DeEr, et al. Chinese Sci Bull January (2010) Vol.55 No.1
3 Feasibility of using proxy record from a single locality to reconstruct EASM strength variations
Several indices based on sea-level atmospheric pressure or
land-sea thermal gradients have been devised to describe
the strength variation of EASM [19–26]. Their correlations
with the deviations from the mean summer precipitation at
160 stations in China over the period of 1951–2000 A.D.
have been analyzed [25]. The analysis revealed a negative
correlation for the middle-to-lower reaches of the Yangtze
River and a positive correlation for regions in the YellowRiver (Huanghe) drainage basin and in a large part of
southern China. This seeming dichotomy in the correlation
reflects in no small measure the vastness and topographic
complexity of China.
Figure 3 shows a comparison of the δ 18O record of stalagmite WX42B with another high-resolution East Asian
Summer Monsoon index time-series published recently by
IPCC[26] for 1850–2004 A.D. based on the reconstruction
by Guo[19] and Allan and Ansell[27]. Incongruence between the two records is apparent even on decadal variations; in at least two of the 20–30 year segments, the variations even show phase reversals. It adds uncertainty to the
proposed causal relationships between summer monsoon
fluctuations and their influence on the Chinese societal/cultural events at large. It also bears on the inadequacy
of assessing the variation of EASM based on proxy series
from a single locality.
4 Caution in using reconstructed EASM variations to reflect precipitation changes over the entire eastern China
Although summer rainfall that annually delivers most of the
moisture to China is closely related to the intensity of
EASM, the interrelation is not a simple, linear one [20]. The
spatial distribution of summer rainfall in China assumes a
quasi-zonal pattern with salient regional differences. For
instance, when the lower reaches of the Yangtze (or Changjiang) and Huaihe Rivers (known as the “Jiang-Huai Drainage Basin”) gets more pluvial than normal, regions to the
north and south of the Huaihe River—Qinling Mountains-North China and South China, respectively—may
suffer severe drought. The relationship between the EASM
intensity and the precipitation amount also displays a regional disparity. In general, positive correlations between
the two are often found in North China, southern South
China, and southeast coastal areas, whereas in upper and
middle reaches of the Yangtze and in the Jiang-Huai Drainage Basin, negative correlations are the norm[20,25].
Many studies have pointed to a connection between the
variation of the EASM index and precipitation patterns
across the whole eastern China[19–25]. On the decadal
scale, there are enough regional differences to dismiss the
concept that strengthening (or weakening) of the EASM
leads to a wet (or dry) condition for the whole eastern China.
For example, Guo et al.[19] illustrated the influence of
EASM on summer rainfall in China during 1951–2000.
Over the period of 1951–2000 A.D., the EASM was the
strongest during 1955–1964 A.D. and the weakest during
1988–1997 A.D. In the ten-year period of 1955–1964, while
North China was wetter than usual, the Jiang-Nan (i.e., the
region south of the lower reaches of the Yangtze River) and
southern coastal areas were drier than normal[19].
Can the Wudu and Zhanjiang records be used as rainfall
indi-cators for the whole eastern China? Efforts to reconstruct
climate in China for historical times have produced yearly
charts of dry/wet series for the period 1470–2000 A.D. [17,
18]. Figure 4 shows the period’s dry/wet series compiled
from data retrieved at 76 stations (Figure 5) covering three
Figure 3 Comparison of the δ18O record of WX42B[5] with the EASM index series of IPCC [26]. In the upper panel, the thick green curve traces the 10-year
running averages for the annual δ18O variations. In the lower panel, annual values and their smoothing through a decadal filter (black curve) are shown.
ZHANG DeEr, et al. Chinese Sci Bull January (2010) vol.55 No.1
separate regions: North China, the Jiang-Huai Drainage
Basin and South China, as well as from some other areas.
Taken together, these sites cover a good part of the whole
eastern China. In many intervals, the D-W index of Jiang-Huai Drainage Basin was different from the other two
regions. In plotting these time-series against each other, one
finds that they all give diffusing patterns (r2 ≤ 0.06) and
caution us against using regional time-series to represent
that of eastern China as a whole.
We further examined the modern-day summer precipitation time-series at Zhanjiang and Wudu. Instrumental data on
summer rainfall at 723 stations in China including Zhanjiang
and Wudu are available for the period of 1951–2004 A.D.
Correlation coefficients for the summer rainfall over the 54
years were separately computed for Wudu vs. remaining 722
stations and for Zhanjiang vs. remaining 722 stations. The
results are displayed in Figure 6(a) and (b), respectively. In
these figures, only significantly correlated stations (r > 0.27)
are shown with the red dots indicating positive correlation
and blue dots, negative correlation. It is seen that on yearly
basis, variations in the summer precipitation at Wudu can
81
only be taken as typical for a limited area in southern Gansu
(Figure 6(a)). As for Zhanjiang, its representation confines to
an even smaller area (Figure 6(b)). Similar computations
were carried out using the 10-year averages of the dryness/wetness ranking data at 120 stations over a 530-year
period from 1471 to 2000 A.D. (Figure 6(c) and (d)). The
results again show that the variation of moisture condition at
these two places can hardly be extrapolated much beyond
their vicinities. Therefore, even on a time scale of tens of
years, it would be indeed hard pressed to take the Wudu and
Zhanjiang records as representative of a large part of China.
Work on high-resolution paleoclimate reconstructions
(e.g., 1–6) is poised to advancing our understanding of
global environmental changes and climate-society interactions. That a stronger (or weaker) EASM brings about more
abundant (or deficit) rainfall over the whole eastern China
could well be valid on longer-than-centennial scales but, on
decadal or shorter intervals it becomes problematic. The
challenge appears to lie in recognizing and coping with the
spatial and temporal variability, as time scale for the system
of interest shrinks.
Figure 4 1470–2000 A.D. time-series of dry-wet indices for the whole eastern China and for three regions therein. Data are from [17,18]. For station locations see Figure 5. Annual values (thin curves) and their 10-year running averages (thick curves) are shown.
82
ZHANG DeEr, et al. Chinese Sci Bull January (2010) Vol.55 No.1
Figure 5 Locations of the 76 sites in eastern China for the D-W index are derived from the historical documentation. Blue dots, green squares, and red
diamonds represent areas of North China, Jiang-Huai Drainage Basin, and South China, respectively. Data from the Tianshui (TS) station are used to cover
for Wudu. HZ = Hanzhong (Data sources: [17,18]).
Figure 6 (a) and (b) Correlations of summer rainfall over the period of 1951–2004 A.D. between Wudu and the other 722 stations, and Zhanjiang and the
other 722 stations in China. (c) and (d) Correlations of dry-wet grades on decadal time scale over the period of 1471–2000 A.D. between Tianshui (representing Wudu) and the other 119 stations, and between Zhanjiang and the other 119 stations. TS = Tianshui which includes Wudu. The red and blue dots
indicate positive and negative correlations, respectively. Data source: China Meteorological Data Sharing Service System [17,18].
ZHANG DeEr, et al. Chinese Sci Bull January (2010) vol.55 No.1
Zhang De’er thanks the Cheng-Kung University for the invitation to visit.
We thank three anonymous reviewers and an associate editor for their
constructive comments on our manuscript. This work was supported by the
Science Council of Taiwan (NSC 97-2628-M-006-014) and the National
Natural Science Foundation of China (Grant Nos. 40672202 and 40599424).
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Wang Y J, Cheng H, Edwards R L, et al. A high-resolution absolute-dated Late Pleistocene monsoon record from Hulu Cave, China.
Science, 2001, 294: 2345–2348
Yuan D X, Cheng H, Edwards R L, et al. Timing, duration, and transitions of the Last Interglacial Asian Monsoon. Science, 2004, 304:
575–578
Wang Y J, Cheng H, Edwards R L, et al. The Holocene Asian Monsoon: Links to solar changes and North Atlantic climate. Science,
2005, 308: 854–857
Wang Y J, Cheng H, Edwards R L, et al. Millennial- and orbital-scale
changes in the east Asia monsoon over the past 224000 years. Nature,
2008, 451: 1090–1093
Zhang P Z, Cheng H, Edwards R L, et al. A test of climate, sun and
culture relationships from an 1810-year Chinese cave record. Science,
2008, 322: 940–942
Yancheva G, Nowaczyk N R, Mingram J, et al. Influence of the intertropical convergence zone on the East-Asian monsoon. Nature,
2007, 445: 74–77
Zhang D E, Lu L H. Anti-correlation of summer and winter monsoons? Nature, 2007, 450, E7–E8, doi:10.1038/nature06338
Yancheva G, Nowaczyk N R, Mingram J, et al. Replying to De’er
Zhang & Longhua Lu. Nature, 2007, 450, E8–E9, doi:10.1038/ nature06339
Eberhard W. A History of China. BiblioBazaar: LLC, 2008. 1–504
Roberts J A G. A History of China. New York. Palgrave Macmillan,
2006. 1–355
Fan W L. General History of China (in Chinese). Vol. III. Beijing:
People’s Publishing House, 1978. 113–427, 376–377
Wu S D. Periods of Liao, Song, Jin and Yuan (in Chinese). Vol. 3. In:
Ge J X. ed. Population History of China. Shanghai: Fudan University
Press, 2005. 1–717
Zhang D E. A Compendium of Chinese Meteorological Records of
the Past 3000 Years (in Chinese with English summary). Nanjing:
Jiangsu Education Press, 2004. 1–3666
Zhang D E. The method for reconstruction of the dryness/wetness series and the winter temperature series in China for the last 500 years
and its reliability. In: Zhang J C, ed. The Reconstruction of Climate
15
16
17
18
19
20
21
22
23
24
25
26
27
83
in China for Historical Time. Beijing: Science Press, 1988. 18–39
Zheng S Z, Zhang F C, Gong G F. On the change in climate wetness
in southeastern China over the past 2000 years. In: Collection of Papers on Climate Change and Extra Long-Term Prediction (compiled
by China Meteorological Administration) (in Chinese). Beijing: Science Press, 1977. 29–32
Zheng J Y, Wang W C, Ge Q S, et al. Precipitation variability and
extreme events in Eastern China during the past 1500 years. Terr
Atmos Ocean Sci, 2006, 17: 579–592
Chinese Academy of Meteorological Sciences, Yearly charts of dryness/wetness in China for the last 500-year period (in Chinese with
English brief introduction). Beijing: Cartographic Publishing House,
1981. 1–332
Zhang D E, Li X Q, Liang Y Y. Continuation (1992–2000) of the
Yearly Charts of Dryness/Wetness in China for the Last 500 years
period (in Chinese). J Appl Meteor Sci, 2003, 14: 379–388
Guo Q Y. The summer monsoon intensity index in East Asia and its
variation (in Chinese). Acta Geogr Sin, 1983, 38: 207–217
Guo Q Y, Cai J N, Shao X M, et al. Interdecadal variability of
East-Asian summer monsoon and its impact on the climate of China
(in Chinese). Acta Geogr Sin, 2003, 4: 569–576
Shi N, Zhu Q G, Wu B G. The East Asian summer monsoon in relation to summer large scale weather–Climate anomaly in China for
last 40 years (in Chinese). Sci Atmos Sin, 1996, 20: 575–583
Zhu C W, He J H, Wu G X. East Asian monsoon index and its inter-annual relationship with large scale thermal dynamic circulation
(in Chinese). Acta Meteor Sin, 2000, 58: 391–401
Sun X R, Chen L X, He J H. Index of land-sea thermal difference
and its relation to interannual variation of summer circulation and
rainfall over east Asian (in Chinese). Acta Meteor Sin, 2002, 60:
164–172
Zhang Q Y, Tao S Y, Chen L T. The inter-annual variability of east
Asian summer monsoon indices and its association with the pattern
of general circulation over east Asia (in Chinese). Acta Meteor Sin,
2003, 61: 560–568
Jiang Y, Zhai P M. Correlation between several indices of Asia
monsoon and China summer main precipitation patterns (in Chinese).
J Appl Meteor Sci, 2005, 16 (suppl): 70–76
IPCC. Climate Change 2007–The Physical Science Basis. New York:
Cambridge University Press, 2007. 1–996
Allan R J, Ansell T. A new globally complete monthly historical
gridded mean sea level pressure data set (HadSLP2), 1850–2003. J
Clim, 2006, 19: 5816–5842